The Development of a Multi Purpose Wet Food Sieving Machine

Abstract

Wet sieving is still a manual operation in tropical crop processing. It is a time consuming operation. Most of the existing wet sieving machines are available in large scale industries and they are too sophisticated to operate and maintain by local processors. Therefore, a motorized starch extracting machine, based on shaking mechanism was designed, fabricated and tested to solve the problem associated with sieving of starch and other agricultural crops in Nigeria. The machine consists of a hopper, a mixing compartment, a sieving compartment operated by a crank and spring arrangement, collecting trays and outlets.  The volumetric flow rate and the capacity of the machine are 0.0206 m3/h and 22.45 kg/h respectively. The test considered concentration at three levels 12.2 %, 14.44 % and 22.77 %. The study showed that the machine performance coefficients and sieving capacity increased with decreasing concentration. Also, highest performance coefficients  of 98% was obtained for sieving of maize while sieving capacity of 16.90g/sm2 was obtained when the machine was used to sieve cassava. A unit of the machine costs N19, 480.00 as at April 2007. The maintenance of the machine is simple and recommended for small holders, local processors and home use.